Urinary Protein Patterns Predict Survival in Primary Systemic Amyloidosis (AL)

Abstract

Serum creatinine level was measured in 153 patients with primary systemic amyloidosis (AL). The median survival of patients with a serum creatinine ≤1.3 mg/dL and >1.3 mg/dL was 25.6 and 14.9 months, respectively (P = 0.007). Patients with a monoclonal lambda light chain in the urine had an inferior survival compared to those with kappa light chain or no monoclonal protein in the urine. The survivals were 12 months, 30 months, and 35 months, respectively (P = 0.01). The total protein excretion had no bearing on survival. Patients with lambda monoclonal protein in the urine excreted 4.56 g of protein per day. Patients with no monoclonal protein and a urinary kappa monoclonal protein excreted 0.52 g/day and 1.09 g/day, respectively. The loss of monoclonal lambda protein in the urine did not result in a higher serum creatinine level. A monoclonal protein was detected in the urine of three-fourths of the patients. The urinary kappa-to-lambda ratio was 1:2.5, but for those patients with nephrotic range proteinuria, the ratio was 1:4.7, suggesting that patients with lambda monoclonal protein in the urine are more likely to have amyloid nephrotic syndrome than patients with no monoclonal protein or kappa monoclonal protein in the urine.